Orders for long-lasting US manufactured goods unexpectedly fell in December as did a gauge of planned business spending on capital goods.
The new figures could cast a shadow on an otherwise bright economic outlook.
The Commerce Department said that durable goods orders dropped 4.3%, pulled down by weak demand for transportation equipment, primary metals, computers and electronic products and capital goods.
Last month's decline in orders for durable goods, which range from toasters to aircraft, was the largest since July and reversed November's revised 2.6% rise.
Economists polled by Reuters had expected orders to rise 1.8% in December after November's previously reported 3.4% advance.
Durable goods orders fell despite a strong rise in aircraft orders at Boeing. The aircraft company reported on its website that it received orders for 319 planes last month compared with 110 in November.
Orders may have dropped because the model used by the US government to iron out seasonal fluctuations was likely anticipating an increase in aircraft orders in December anyway.
Excluding transportation, orders fell 1.6%, the biggest decline since March, after edging up 0.1% in November.
While durable goods data is volatile from month to month, details of the report could support views that factory activity will cool off early this year after output grew at its fastest pace in nearly two years in the fourth quarter.
Non-defence capital goods orders excluding aircraft, a closely watched proxy for business spending plans, fell 1.3% after rising by a revised 2.6% in November.
Economists had expected orders for these so-called core capital goods to increase 0.5% in December after a previously reported 4.1% surge in November.
Shipments of core capital goods, which are used to calculate equipment spending in the government's measure of gross domestic product, slipped 0.2% last month.
US home prices edged lower in November
US home prices fell slightly in November, the S&P/Case-Shiller home price index showed today, in some new evidence that the hot housing market is slowing down.
The Case-Shiller index for 20 leading cities fell for the first time since November 2012, losing 0.1% in the month.
Nine of the 20 cities lost ground, nine saw prices rise and there was no change in two cities.
On a seasonally adjusted basis, prices in November gained 0.9%. Year on year gains remained strong, rising 13.7%.
But with mortgage interest rates rising, analysts said the strong market of the past two years and the double-digit annual price gains could soon be over.
Las Vegas, one of the worst-hit cities in the US housing crisis, continued to bounce back with a 0.6% gain in the month, and 27.3 percent in the year. Also strong were Miami and San Francisco, where housing price gains driven by booming tech industry salaries have become a political issue.
But other hot markets of the past two years, Washington, New York, Chicago, Portland and Denver, all showed a monthly fall.